Grinders



D. W. HECK Jan. 6, 1959 GRINDERS Filed Jan. 31, 1958 INVENTOR Daniel W. Heck.

United States Patent GRINDERS Daniel W. Heck, Tarentum, Pa., assignor to Allegheny Ludlum Steel Corporation, Brackenridge, Pa., a corporation of Pennsylvania Application January 31, 1958, Serial No. 712,511

14 Claims. (Cl. 51-188) This invention rel-ates to the polishing and grinding of metals and particularly to grinders and polishing and grinding belts employed in the surface preparation of flat rolled metal products.

In the manufacture and processing of flat rolled metal products it is frequently desirable and sometimes necessary to provide a predetermined ground or polished finish to the surface of the metal. Such a finish is often desirable to minimize the necessity of metal finishing of subsequently fabricated articles or may be desirable from the standpoint of removing unattractive or unsound surface conditions frequently resulting from descaling and heat treating practices. For example, stainless steel cold rolled sheets are commonly polished on endless grinder belts having an abrasive material of from about 120 to 150 grit size on the surface thereof to obtain what is known as a No. 4 finish. Such a finish is not only popular but also is a required intermediary step in securing even finer finishes which are commonly obtained by subjecting the sheet to further polishing and grinding operations. The fabrication of titanium and titanium alloy flat strip and sheet also requires surface preparation involving grinding and polishing with various size grit materials.

Metal sheets are conventionally ground and polished by passing them through grinding and polishing machines which impress upon their surfaces continuously traveling endless grinding and polishing belts. These belts are propelled over the flat surfaces of sheets by means of motivated rolls. The abrasive surface of the grinding and polishing belts consists of an abrasive material bonded to the surface of the belt of the size required to obtain the desired finish. Such grinding belts may be purchased on the open market in a wide variety of Widths and sizes; however, grinding machines are generally designed to accommodate a belt of a predetermined width. So long as the metal sheets being ground or polished are of a width that requires the maximum width belt that the rolls of the machines will accommodate, an efficient use of the abrasive surface is experienced. However, the metals industry in responding to a variety of orders must frequently polish and grind metal sheets of substantially less width than the maximum width that may be employed in the polishing and grinding machines. It would follow that to polish narrower sheets one should employ narrower polishing belts to conserve the use of abrasives. However, such is not possible in that if belts of less than the maximum predetermined width are employed, such narrow belts wear into the surface of the rolls supporting the grinding belt at the belt edges with the result that wider belts may not be used thereafter to polish wider sheets without changing the polishing roll of the grinding machine. The grooves caused by the wearing in of the narrow width belts on wide rolls prohibit the use of the wide belts on these rolls to polish the wider sheets because if the grooved rolls are so employed, defects or undesirable marks will occur on the Wider sheets in the locality of such grooves.

Although the grooving effects of polishing belts are no problem where the same size of belts is always employed,-

it can be seen that where various width belts are usedmately a 52-inch belt in order to prevent damage to the roll thus wasting 8 inches of abrasive surface. If a 44- inch belt were to be employed, the roll could not thereafter be, employed to support 52-inch belts to grind flat sheets up to a maximum width of about 48 inches since the grooves imparted to the rolls by the 44-inch belt make it impossible for the rolls to thereafter uniformly support the wider belts. The time and expense involved in changing rolls on such machines is even more inefiicient and wasteful than the waste of large amounts of abrasive surface. Such waste of abrasive materials is common in the metal finishing industry today. A method of eliminating this waste is a highly significant advance in the art of metal treatment.

It has now been found that by the means of the present invention grinding and polishing belts of various widths may be freely employed to grind the surface of metal sheets of various width without affecting or destroying the usefulness of the rolls employed in propelling such a belt. Thus a great savings in abrasive materials is effected.

In general the present invention relates to a. means whereby various width polishing belts may be employed in conjunction with a single width roll in a grinder'without damaging the roll by edge grooving. The polishing belts are bonded on their inside non-abrasive surfaces to strips of a flexible material that extend beyond the edges of the grinding belts and contact the rolls and prevent edge wear on the surface of the roll.

It is therefore an object of the present invention to provide for utilizing various widths of grinding and polishing belts on polishing and grinding machines without damaging the rolls of such machines.

It is also an object of the present invention to provide a grinding and polishing belt that will not groove the rolls of polishing machines.

A still further object of the present invention is to provide a polishing and grinding belt with a protective edge tape bonded to the non-abrasive side of the belt and extending beyond the edge of said belt to protect the grinding roll surface.

Other o-bjects and advantageous features will be obvious from the following description when taken in con-- junction with the accompanying drawing in which:

Figure 1 is a view in elevation with parts broken away of a grinding and polishing belt constructed in accordance with the present invention;

Fig. 2 is a cross sectional view of the belt of Fig. 1

taken along lines IIII thereof;

Fig. 3 is a cross sectional View similar to Fig. 2 of a polishing and grinding belt that constitutes another modification of the belts of the present invention; and

Fig. 4 is a schematic illustration of a grinding and polishing machine that may employ the belts of Figs. 1 through 3.

In Figs. 1 through 3 there are shown. endless grinding and polishing belts constructed in accordance with. the

present invention. In each of the figures break-awayareas 11 illustrate that the belts may be of comparative: In Figs. 1 and 2' the abrasive backing material is shown as 13, which in' this embodiment shown to be afibrousumaterial such;

1y greater or less width than shown.

ascotton impregnated with a resin. The abrasive material glued to the outer surface of the hacking material is shown at 15. Flexible fibrous tapes 17 are bonded along each of the edges-of and to the non-abrasive underside of the backing material 13 as shown at19 in Fig. 2. The bonded fiber strips are clearly shown in Fig. 1 by break-away area 20. The tapes 17 in this embodiment can be seen to be not more than half the thickness of the abrasive belt formed by the backing 13 and the abrasive surface and extend beyond the outer edges of the belt, as shown at 21, for approximately /a inch.

In the embodiment shown in Fig. 3 the abrasive backing material 33 is shown to be a laminated fibrous material such as'sheets of paper. The flexible tapes shown as 37 are constructed of an'impregnated cloth similar to the abrasive backing 13 of Figs. 1 and 2 and when applied to the belt extend beyond the belt for approximately /8 inch -as shown at 41. The tape is seen to be somewhat thicker than the overall thickness of the abrasive belt. as shown at 43. The beveled construction of flexible tape 37 minimizes the possible effect of the thickness of the tape from detracting from the flatness of the grinding or polishing surface of the contacting area that is maintained in contact with and effects the grinding and polishing of metal sheets.

Fig. 4 schematically shows a metal sheet 51 being ground and polished by an endless polishing and grinding belt53. The belt 53 is seen to be composed of the abrasivebelt itself being the outer section 55 and the flexible tape, such as is illustrated in Figs. 2 and 3 as l7.and 37, at 57. Sheet 51 is held in position for grinding by opposed guide rolls on either side of the grinding area 59 as shown generally at 61. Additional rollers to support sheet 51 are shown generally at 63. A steel backingroll 65'supportsthe sheet near the area of grinding 59. Grinding and polishing belt 53 is motivated by a motor 67 con nected to a suitable source of supply and which is connected by any suitable mechanical linkage 69 to drive roll 71. Drive roll 71 is constructed of a steel core 73 and a rubber case 75 which is provided with serrations (not shown) occurring at about a 40 angle from the vertical on the surface thereof. The combination of rubber case and serrations edects greater friction and contact between the roll 71 and the belt 53 for driving the belt.

Rolls 77 and 79 are steel guide and tension rolls.

7 These rolls are of slightly greater diameter near the center than near the edges and serve to keep the belt 53 straight on the rolls and avoid side movement. Roll 77 is provided with an adjustable means of taking up and releasing tension on the belt 53. The means shown in this schematic drawing, which is an illustration only, shows a spring 81 creating a tension on an arm 33 which effects an upward directed pressure on roll 77 thus maintaining the predetermined tension on belt 53. It can easily be seen that adjustment of the tension on spring 81 will affect the pressure on roll 81 and thus the tension on belt 53. Roll 85 carries the abrasive belt 53 over sheet 51. This roll also has a steel core 87 and a serrated rubber case 89 similar to roll 71 that effects increased friction and thus better contact with the backing material of belt 53 and avoids slippage while effecting pressure against the belt 53 and sheet 51.

It can be seen from the above discussion and drawings that while belt 53'is passing over rolls 71, 77, 79 and 85 flexible backing tape such as is shown in Figs. 1 and 2 as 17, Fig. Bets 37 and Fig. 4 as 57 prevents the edges of the grinding belts proper from coming into contact, Wearing or abrading the rolls and particularly roll 85 Which carries belt 53 into contact with sheet 51. The edges o'fthe various belts must obviously wear their way through the protective tape before scoring of the roll is effected. The polishing and grinding belts will have long been worn out before'this eventuality occurs. It is to be noted that in the illustration presented by Fig. 4 only roll 85 The tape 37 is also seen to be beveled a is adversely affected by employing the various width belts without the improvements of the present invention in that only this roll has a direct effect on the polishing and grinding operation of sheet 51.

It is substantially immaterial whether the surface of roll is constructed of metal, rubber or some other substance in that all such rolls experience the effect of edge grooving where prior art belts Without the protective tape of the present invention are employed. Also, the grind ing machine may contain only two rolls such as drive roll 71 and roll 85, such as is the case in small bench grinders.

Commercially available grinding and polishing belts are supplied with a variety of backingand abrasive materials. The most common backing materials are paper and cloth. Paper backing of tapes such as are supplied by Behr Manning Corporation of Troy, New York is generally S-ply l30-pound paper (a ream or 430 sheets of 9-inch by 11-inch paper weighs 130 pounds). The cloth backing employed in other tapes is generally heavy woven cotton cloth impregnated with a stiffening material. The grit size of such polishing belts may be anygrit desired; however, belts-are available commercially with grits-running all the way from 16 to 600. The abrasive material itself may be any hard particulant material; however, the most common abrasive that is commercially available is a mixture of alumina and silicon carbide. The abrasive itself may range in grit size from 16 grit through 600 grit, depending on the finish desired, and is generally gluedto the surface of the belt with an animal hide glue. The belts may be obtained in any widths, but are available commercially in standard widths of from about 1 inch up to and'exceeding inches. Suchbelts may be obtained in overall gauges (backing plus abrasive) of from about ;005 inch to .06 inch depending on the type of backing and abrasive employed.

A large varietyof commercial polishing and grinding machines is available. Generally these machines vary to accommodate belts anywhere from 20 feet 3 inches in circumference such as employed by a type 455 Madison polishing and grinding machine manufactured 'by Madison Machine Company of Rockford, Illinois (similar to Fig. 4) down to 20 inches in circumference for small drum bench grinders. Another popular belt size is a 10- foot 6-inch circumference belt such as is employed by the 2 roll grinders manufactured by the Hill Acme-MachineCompany of Cleveland, Ohio.

Inthe practice of the present invention a stripof flexible material herein referred to as tape which may be a commercially available tape with one adhesive surface or maybe a flexible material selected at random, but which possesses strength comparable to that of backing materials for grinding and polishing belt, is bonded to the non-abrasive surface of an endless grinding and polishing belt. The tape may be of any width and may project inwardly from the edge of the belt on either side until meeting in the center of the belt. However, to avoid possible adverse effects on the material being polished it is desirable to prevent the width of the tape from exceeding the overlap of the polishing belt on the steel being ground. For practical considerations this will generally be in the range of from /2 to 2 inches and preferably in the range of from 1 to 2 inches depending on operating conditions. In order for the tape to effectively avoid'edge wear caused by the polishing belt it should preferably extend beyond the edge of the belt a distance of at least about A of an inch. In practice, the tape may extend an indefinite distance beyond the belt, the only limitation being that the extension must bepractical for the polishing and grinding machinebeing employed. However, it is preferred not to extend the edge of the tape more than about 1 inch beyond the edge of the belt, particularly, if the entire tape has an-adhesive surface such as is the c-ase if commercially-available tapes areemployed. The thickness of the tape is not critical; however, should the tape be thicker than the polishing and grinding belt itself it may adversely affect polishing, particularly, if it extends inwardly near or beyond the area Where actual grinding and polishing of the sheet is taking place within /2 to 2 inches of the edge of the belt. In practice it is sometimes advantageous to employ tapes of a gauge up to twice the thickness of the polishing and grinding belts; however, it is preferred to maintain the tapes at a thickness not in excess of the thickness of the polishing and grinding belt to which it it attached. It is also sometimes advantageous to bevel the inside edges of the tape as shown in Fig. 3 where the thicker tapes are used to avoid marring the edges of the sheets being ground and polished.

The tape may be constructed of any fibrous or synthetic material such as paper, cloth or resinous material. For example, tapes manufactured from natural .or synthetic elastomer, polyethylene or other synthetic materials may be effectively employed. In a specific case, a commercially available masking tape identified as Scotch Wetordry Masking Tape No. 202 and which is stated as having been made under one or more of Patents 2,236,527, 2,269,712, 2,350,369, 2,410,053, 2,410,078 and 2,410,079 has been successfully used in practicing this invention. In this embodiment the tape used was approximately 1 inch wide and about .01 inch thick and had an adhesive on one surface thereof. Such tape was secured to a 3-inch wide 60 grit belt mounted on the drums of an ordinary 28-inch bench grinder designed to normally accommodate 5-inch wide belts. The tape attached to the non-abrasive side in the manner shown by Figs. 1, 2 and 3 ,was permitted to extend beyond the edges of the belt from about inch to Mr inch. The grinder was employed for approximately 8 hours while impressing various metallic articles against this surface. At the conclusion of this time it was found that the tape overlapping the edges of the belt had successfully prevented edge grooving of the rolls of the grinder.

The bonding adhesive that unites the tape and the nonabrasive backing of the grinding and polishing belt may be any adhesive of sufiicient strength to hold the tape to the backing during the grinding operation. Other commercially available tapes satisfactory for use in practicing this invention are sold by the Behr Manning Corporation of Troy, New York and are designed as No. 101 Bearthese tapes that extend beyond the belts are of no con-.

sequence and do not inhibit the use of the belt in that these surfaces do not contact the grinder rolls, the metal being polished or the grinding belts. A cementor glue that may be employed to bond tapes other than the commercially available pressure-sensitive tapes in lieu of such commercially available tapes may be animal glue or any good adhesive such as rubber cements.

' As examples of the present invention commercially available pressure sensitive tapes manufactured by, Behr Manning Corporation were bonded to the non-abrasive side of polishing and grinding belts by pressing the adhesive surface of the tapes against the inside surface of the belts in the manner shown in Figs. 1 through 3 of the attached drawings. The tapes were all either /2 inch or 1 inch wide and extended beyond the edges of the belts approximately 4: inch. These tapes had the following specifications:

6 N0. 101 Bear Brand Flatback Masking Tape:

Construction: Saturated crepe paper, rubber base,

pressure-sensitive adhesive Physical properties: Tensile strength pounds per inch of width is 20. Elongation: 12% Adhesion: 35 oz. per inch of width Gauge'in mils is 10 121 Bear Brand'Flatback Masking Tape:

Construction: A saturated flatback paper, rubber base, pressure-sensitive adhesive.

Physical properties: Tensile strength poundsper inch of width is 20.

Elongation: 12%

Adhesion: 34 oz. per inch of width Gauge in mils is 9 Heat resistance: 250 for one hour 131 Bear Brand Flatback Masking Tape:

Construction: Saturated 4 mil rope paper hacking,

rubber base, pressure-sensitive adhesive.

Physical properties: Tensile strength pounds per inch of width is 45.

Adhesion: 65 oz. per inch of width Gauge in mils is 8 Heat resistance: 250 for one hour The above identified tapes or the paper backing materials of these tapes are impregnated with a strengthimparting agent such as a rubbery butadiene copolymer of the type disclosed in United States Patent No. 2,726,967 to Eger et al. The pressure-sensitive adhesive is of the rubber-resin type such as the following:

Synthetic resin backsize and polyvinyl carbamate release agents such as described in United States Patents 2,547,980 and 2,532,011, respectively, were employed in the manufacture of these tapes.

The polishing and grinding belts employed were 12 inches wide plus 126 inches in circumference and exhibitedvarious grit sized abrasive surfaces. For example, individual tests were conducted while employing 60, 80, and grit belts. The backing materials of the belts were resin impregnated paper and in some instances resin impregnated cotton cloth. The gauges of these belts range from .016 inch to .035 inch.

All the tests were conducted on Hill Acme polishing and grinding machines made by the Hill Acme Company of Cleveland, Ohio. These machines consist of two rolls aligned vertically with respect to one another on which the belts are mounted. Both rolls contain a steel core and a rubber case. The speed of the machine carried the abrasive belt over the surface of the sheet being ground and polished at a'rate of about 4900 feet per minute.

The belts of the various grit sizes, backing materials and tapes were mounted on 28 and 36-inch wide rolls and employed to grind eleven inch wide stainless steel (AISI type 302) sheets. Grinding was continued for,

from 3 to 4 hours for each test. No edge wear or grooving occurred on either of the rolls during or after testing.

One 1-2-inch wide by 126-inch long, 60 grit, approximinutes.

ase noei ma tely .Q2 7 inch g'auge belt, which constructed of a resin impregnated paper-backing (knowneornmrcially asfiO-E Resinized Adalo'x Paperlwas bonded with a one-half inch No. 101 tape (described above) along one edge and a one inch No. 121 tape along theother edge. Both tapes extended beyond the edge of the belt approximately /8 inch. The belt was mounted on the 28-inch rubber case roll of the Hill Achie machine and employed to grind an 11-inch wide stainless steel sheet for. approximately 3 hours totaltime. .No edge effect was observed. The No. 121 tape was then removed and the test was continued for a total time of 6 hours and At the conclusion of thetest the roll was grooved from the untapcd edge or where theNo. 121 tape had been removed but was not grooved at the taped edge. H y

A similar endless belt to that described above was bonded on one edge only with one-half, inch No. 101 tape inch overlapi) Marking of the roll was observed at the untaped edge of the belt after about 2 hours of grinding on an 11-inch wide stainless steel sheet. Edge effect was pronounced at the untaped edge after about 10 hours and 30 minutes of testing without any accompanying edge effect at the taped edge of the belt.

I claim:

1. In a belt grinder having rolls adapted to utilize an endless grinder belt having a predetermined width, the combination therewith of, a grinder belt having a vwidth less than said predetermined width, and tape of flexible material applied lengthwise of and secured to atleast a portion of the back of said grinder belt and disposed to extend beyond each of the edges of the belt to prevent said edges from scoring the rolls whereby the rolls may be later used with a grinder belt having said predetermined width.

2. In a belt grinder having rolls adapted to utilize an endless grinder belt having a predetermined width, the combination therewith of, a grinder belt having a width less than said predetermined width, and tape of fibrous material impregnated with a binder applied lengthwise of and secured to at least a portion of the back of said grinder belt and disposed to extend beyond each of the edges of the belt to prevent said edges from scoring the rolls whereby the rolls may be later used with a grinder belt having said predetermined width.

3. In a belt grinder having rolls adapted to utilize an endless grinder belt having a predetermined width, the combination therewith of, a grinder belt having a Width less than said predetermined width, and tape of flexible material applied lengthwise of and secured to at least a portion of the back of said grinder belt and disposed to extend beyond each of the edges of the belt for a distance of between about /1 inch and 1 inch to prevent said edges from scoring the rolls whereby the rolls may be later used with a grinder belt having said predetermined width.

4. In a belt grinder having rolls adapted to utilize an endless grinder belt having a predetermined width, the combination therewith of, a grinder belt having a width less than said predetermined width, and tape of fibrous material impregnated with a binder applied lengthwise of and secured to at least a portion of the back of said grinder belt and disposed to extend beyond each of the edges of the belt for a distance of between about ,5 inch and 1 inch to prevent said edges from scoring the rolls whereby the rolls maybe later used with a grinder belt having said predetermined width.

5. In a belt grinder having rolls adapted to utilize an endless grinder belt having a predetermined width, the combination therewith of, a grinder belt having a width less than said predetermined width, and fibrous tape applied lengthwise of and securedto at least a portion of, the back of said grinder belt, the fibrous tape having a thickness less than twice the thickness of'said belt and 8 being disposed to extend beyond each of the edges of the belt fora distance of between about /1 inch and 1 inch throughout the length of the belt to prevent said edges from scoring the rolls whereby the rolls may be later used with a grinder belt having said predetermined width.

6. A belt of the polishing and grinding type comprising, a continuous belt of flexible strip material having abrasive material carried on the outside surface of said belt, and flexible tape disposed lengthwise of the belt along each edge thereof and being bonded to at least a portion of the inside surface of said belt adjacent the edges thereof and disposed to extend beyond each of the edges'of the belt.

7. A belt of the polishing and grinding type comprising, a continuous belt of flexible strip material having a coating of abrasive material carried on the outside surface of said belt, and tape of flexible strip material applied lengthwise and bonded to at least a portion of the inside surface of said belt and disposed to extend beyond each of the edges of the belt for a distance of between about A irich and 1 inch to prevent said edges from scoring the surface of the rolls of belt grinders in which said belt is employed. 7 p

8. A belt of the polishing and grinding type comprising, an endless belt of flexible strip material having abrasive material carried on the outside surface of said belt and tape of flexible strip material applied lengthwise and bonded to at least a portion of the inside surface of said belt, the tape having a thickness no greater than twice the thickness of said belt and being disposed to extend beyond each of the edges of the belt for a distance of between about inch and 1 inch to prevent said edges from scoring the surface of the rolls of belt grinders in which said belt is employed;

9. In the process of polishing and grinding flat metal products on a grinder wherein said products are contacted by the abrasive surface of an endless belt that is revolving about a plurality of rolls disposed to hold and drive said belt, the improvement comprising the steps of, applying a loop belt having two strips of flexible material carried on the inner surface of the loop beltto extend beyond the edges thereof to the grinderrolls, and driving said loop belt with the two strips in contact with the rolls of the grinder to thereby prevent the edges of said loop belt from contacting and scoring the rolls of the grinder. v 7 n 10. A belt of the polishing and grinding typefcomprising, an endless loop belt of flexible strip material having abrasive material carried on the outer surface of the loop, a plurality of strips of flexible material disposed to seat in contacting engagement against the inner surface of the loop adjacent each of the outer edges of the belt with a portion of each of said strips extending beyond the edge associated therewith, and means for securing each of said strips to. the inner surface of the loop throughout the contacted areas thereof. y

11. In a belt grinder having rolls adapted to utilize an endless loop grinder belt having a predetermined width, the combination therewith of, an endless loop grinder belt having a width less than said predetermined width, strips of fibrous material impregnated with a binder applied lengthwise of and in contacting engagement with the inner surface of said loop beltand disposed to extend a predetermined distance beyond each of the edges of said loop belt, and adhesive means disposed between the contacting areas of said strips and the inner surface of said loop belt for securing said strips to said loop belt, said strips being of a length to extend throughout the length of said loop belt whereby the extension of said strips beyond the edges of said loop belt prevents said edges from scoring the rolls so that the rolls can be later used with a grinder belt of said predetermined width.

12. In a belt grinder having rolls adapted to utilize an endless loop grinder belt having a predetermined Width,

the combination therewith of, an endless loop grinder belt having a width less than said predetermined width, and a layer of flexible fibrous material carried by at least a portion of the inner surface of said loop belt throughout the length thereof and disposed to extend outwardly beyond each of the edges of said loop belt to provide a flexible cushion therefor and prevent said edges from scoring the rolls whereby the rolls can be later used with a grinder belt having said predetermined width.

13. In a belt grinder having rolls adapted to utilize an endless grinder belt, the combination therewith of, a grinder belt having tape of flexible material applied lengthwise of and secured to at least a portion of the back of said grinder belt and disposed to extend beyond each of the edges of the belt for a distance of between about li inch and 1 inch to prevent said edges from scoring the rolls.

14. A belt of the polishing and grinding type comprising, a continuous belt of flexible strip material having abrasive material carried on the outside surface of said belt, and flexible tape disposed lengthwise of the belt along each edge thereof and being bonded to at least a portion of the inside surface of said belt adjacent the edges thereof and disposed to extend beyond each of the edges of the belt, said flexible tape having a beveled edge along the portion of the tape bonded to the inside surface of said belt.

No references cited. 

